Gzip Files requires native tooling

[Rafiot]

Is there a reason you're not using the gzip module to handle pure gzip file? You do that for .tar.gz, so it is confusing.

And if not, do you mind if I implement a pure python module to handle simple gzip files without requiring 7zip?

[jbremer]

Thanks, you're right! I think the most important aspect for me is keeping up performance; so preferably we have such pure Python implementation with opt-in 7z-based module, i.e., if 7z is installed it should opt for that method. This requires a bit more work, though.. feel free to PR as suggested in the meantime.

[Rafiot]

Sounds good, I'll push a PR ASAP

[jbremer]

What I suggested is basically what I described in #25, BTW.